Mold fob



F. E. THOMES.

MOLD FOR MAKING METAL CASTINGS. v APPLICATION FILED JULYZI, 1919.RENEWED JULY 25.1921. 1,410,777.

Patented Mar. 28, 1922. Fly. 3.

UNITED STATES FATENT FOEFEQE.

FRANK E. THOMES, OF PORTLAND, MAINE.

MOLD FOR MAKING METAL GASTIN'GS.

To all whom it may concern:

Be it known that I, FRANK E. THoMEs, a citizen of the United States,residing at Portland, in the county of Cumberland and State of Maine,have invented certain new and useful Improvements in Molds for MakingMetal Castings, of which the following is a specification.

My invention relates to molds for making metal castings and it relatesparticularly to the application of the principles underlying theinvention shown in my application No. 203,840, filed Nov. 24, 1917, tovarious forms of castings and particularly to the making castings ofsteel and other metals having such shrinkage.

My original invention was based on the idea of feeding the casting froma preheated shrink head or chamber, the preheating being accomplished bypouring the casting through the shrink head to maintain the feedingmetal at a high degree of heat and fluidity.

In making steel castings, there are many forms which it is diflicult tomake without shrink holes and cracks on account of the great shrinkagewhich takes place in the metal as it cools and consolidates.

I have found that the mold described and claimed in my said applicationis well adapted for gating and feeding many forms of steel castings andparticularly those which have been diflicult to make under the oldmethod. There are various forms, however, which I have found to requirespecial modi fications of my original invention and my aim has been toadapt the principles of that invention to substantially all forms ofcasting which may be met with the foundry practice.

In the mold described in my said application, the shrink head, orfeeding chamber, received its metal from a skim gate which enclosed andprotected the upper end of the shrink head and the metal was dischargedlaterally from the shrink head intothe matrix, the shrink head beinglocated as closely as possible at the side of the matrix.

In applying this-mold to castings of different kinds, I have found itdesirable to make various changes and modifications to Specification ofLetters Patent. Patented 1 28 1922 Application filed. July 21, 1919,Serial No. 312,381.

Renewed July 25, 1921. Serial No. 487,516.

suit th peculiar characteristics of the castings and particularly inadapting it to castings having heavy sections difficult to feed.

I have found, for instance, that in the case of pulleys and gears havinghubs of heavy section, it is desirable to enter the matrix from the toprather than from the side as in the case of my original mold.

If the shrink head, or feeding chamber, were to be located directly overthe heav section and fed down through, the hydrostatic head and velocityof the metal as it entered the matrix would cause an elongated body ofvery hot metal to penetrate vertically into the heavy section of thematrix and when the casting cooled cracks and shrink holes would be verylikely to result.

To overcome this defect and to adapt my shrink head to top feeding andpouring, I arrange the shrink head above and at one side of the hub orother heavy section and arrange the outlet to the shrink head so that itopens laterally and thence downwardly into the heavy section of thecasting. In this manner the metal, instead of pouring directly downward,overflows into the heavy section of the casting with a gentle motion andtends to make an even distribution of the melted metal throughout thematrix.

In some instances where a casting is relatively deep, I have found itadvantageous to form a runner on the lower end of my shrink head and toconnect the runner with the lower portion of the matrix so that thelatter will be under-poured while laterally connecting the shrink headwith the upper portion of the casting-to provide for the effectivefeeding. Where in a deep casting there is a heavy section above andbelow, I feed both the upper and lower portions with a shrink head foreach, connecting the two shrink heads by a runner so that all parts areeffectively poured and fed.

A further improvement in my mold I secure by forming a small indicatingpassage extending from the matrix to the top of the cope and terminatingsubstantially at the same level as the top of the shrink head. Bycarefully watching the indicating opening the foundryman can tell whenthe shrink head is full although the latter is out of sight, and thusprevent the metal from overflowing irom the top of the shrink head andfilling the runners and other passages through which the metal entersit.

111 the accompanying drawing, I have illustrated several of themodifications and improvements above referred to and which constitute mypresent invention.

Referring to the drawing:

Fig. 1 is a plan view of my mold formed for top pouring of a heavysection,

Fig. 2 is a section on the line 11 of Fi 1,

ig. 3 is a plan view of a mold for deep castings showing a runner forunder-pouring,

Fig. 4 is a sectionon the lin 22 of Fig. 2 and Fig. 5 is a centralsection of a mold adapted to making a deep casting with heavy sectionsabove and below.

Similar reference numbers indicate similar parts in the drawing.

Referring to Figs. 1 and 2, 1 represents the cope and 2 the nowel, ordrag, and 3 represents the matrix, which, in this instance, is formedfor casting a gear with a heavy hub section.

The shrink head 4 is formed in the sand above and slightly at one sideof the hub and connects with said hub by a passage 5 which leads firstlaterally and then downwardly into the hub portion of the matrix.

The lower end of the shrink head is hollowed out into a basin 6 slightlybelow the lateral outlet 5.

As the result of this construction, the metal first falls into the basin6 through the pouring opening and gently overflows into the hub sectionof the matrix evenly distributing itself throughout the matrix andwithout any tendency to force a vertical stream of hot metal into thehub portion of the matrix.

The shrink head is fed through a pouring basin formed in a block of corematerial 7 which rests on the top of the cope.

-The basin proper consists of a conical opening 8 terminating at itslower end in a vertical cylindrical space 9. A horn sprue 10 extendsfrom the'side of the opening 9 and enters the upper end of the shrinkhead 4.

Thus, when the stream of hot metal falls into the pouring chamber 8, asit often does from a considerable height, it overflows through the hornsprue 10 into the shrink head and again overflows from the shrink headinto the matrix so that the harmful eifect of the hydrostatic head andthe velocity of the stream of metal entering the matrix is entirelyeliminated and the metal w thin the matrix approaches uniformity oftemperature.

For the purpose of checking the pouri operation so that the pouringbasin and its connection will not be filled, 1 form a small indicatingpassage 11 which extends from the upper portion of th matrix to anopening through the to of the cope, said opening being substantially ofthe same level as the top of the shrink head.

By watching the upper end of the indicating passage 11, the shrink headcan be exactly filled without any overflow which may extend into anysprues or runners with which it may be connected.

Referring to Figs. 3 and 4, my invention is shown as applied to arelatively deep casting having a heavy section at the top, the mold inthis case being formed for casting a heavy cylinder 12 with a flange orcollar 13 at its upper end. The shrink head 14 is formed in thecope andopens laterally with a very short connection into the edge of the collar13.

The casting is under-poured by means of a runner, or sprue, which leadsfrom the lower portion of the shrink head 14 to the lower portion of thematrix. I As here shown, a vertical runner 15 leads from the bottom ofthe shrink head and connects at its lower end with a horizontal branchrunner 16 which enters the bottom of the matrix, the casting'is pouredby means of a pouring basin 17 having a horn sprue 18 similar to thatshown in Fig. 2 and the sprue 18 is of substantially the same size asthe runner 15.

In pouring the casting, the metal drops to the lower end of the shrinkhead and flows down through the runner 15 at substantially the same rateat which it enters the shrink head.

The result is that the casting is poured from the bottom upward andsubstantially no metal enters at the flange until the matrix is full andthe metal passes in laterally from the shrink head. i I

As aresult of this construction of the mold. the metal all passesthrough 'the'shrink head preheating the same to a high degree and themetal. enters the matrix with very little current or disturbance thustending to preserve a uniform temperature throughout the matrix and inthis manner preventing voids and cracks;

As the shrinkage takes place in the casting, the metal from the shrinkhead flows in to compensate for the shrinkage, this being at a highertemperature and more liquid in consistency than any portion of thematrix.

An indicator opening 11 is formed in the cope in the same manner asshown in Fig. 2. Referring to Fig. 5, I have shown a modificationadapted to a deep casting having a heavy section at the top and also atsome point lower down in the casting.

The illustration isa mold formed for east- 1 ing a. lac-celled nozzle,or base, designed to form the lower end of a pulp digester which is atall structure. formed of steel plates with a tapering lower end.

These castings are built to stand a very high pressure and greatdifficulty has been experienced hitherto in casting them without shrinkcracks which greatly weakened the casting.

The matrix in Fig. 5 represents the casting which has a heavy annularsection 19 at the upper end and a heavy annular section 20 between thetwo ends.

For the purpose of feeding this casting, I make use of a shrink head 21located at the edge of the flange 19 and closely adjacent thereto with asecond shrink head 22 closely adjacent to and connected with the annularsection 20, the two shrink heads being connected by a runner 23.

The metal is poured through a pouring basin 24 similar to the pouringbasin shown in Figs. 2 and l.

The metal enters the shrink head 21 thence passes through the runner 23,the shrink head 22 and thence into the matrix.

The matrix is gradually filled through the shrink head 22, the metalfrom the Shrink head '21 not entering until the top of the casting isreached.

The heavy sections 19 and 20 are fed during the shrinking period by thelarge body of very hot metal contained in shrink heads 21 and 22 whichhave been preheated by having all the molten metal mass through them andas a result the casting comes out free from shrink cracks or voids.

The modifications above described are all based on the same principleshown in my original application Serial No. 302,840, filed Nov. 24:,1917 that is, by pouring the casting through a preheated shrink head andare designed to adapt the principle to castings of varying shape andsize and particularly to apply it to those forms where it has beendifficult or impossible to make sound steel castings without cracks andshrink holes.

I claim:

1. In a mold for making metal castings, the combination of a matrix, ashrink head above the level of said matrix having apouring opening andwith a feeding passage leading laterally from said shrink head andthence downwardly into the upper portion of the matrix.

2. In a mold for making metal castings, the combination of a matrix, ashrink head communicating with said matrix, a pouring basin having ahorn sprue leading from said pouring basin to said shrink head.

3. In a mold for making metal castings, the combination of a matrix, ashrink head above the level of said matrix having a passage leadinglaterally therefrom and thence downwardly into the upper portion of saidmatrix, a pouring basin above said shrink head having a horn sprueentering the said shrink head.

4:. In a mold for making metal castings, the combination of a matrix, ashrink head communicating therewith, a pouring opening communicatingwith said shrink head and an indicator opening extending from the matrixto the exterior of the top of the mold and at a point substantially at alevel with the top of the shrink head.

5. In a mold for making metal castings, the combination of a matrix, ashrink head communicating therewith and having a pouring opening,'arunner entering the bottom of the shrink head and communicating with thelower portion of the matrix.

6. In a mold for making metal castings, the combination of a matrix, ashrink head connecting therewith and having a pouring opening, a runnerentering the bottom of said shrink head and communicating with the lowerportion of said matrix, the said runner and pouring opening being of substantially the same size whereby the matrix will be filled through therunner and fed through the shrink head.

